It is well-known from the prior art to use chemical solvents such as amines and physical solvents such as methanol or triethylene glycol dimethylether (TEGDME) to carry out the deacidizing operation. Chemical solvents afford the advantage of absorbing acid gases, even in very low proportions in the gas to be treated. They thus allow to obtain high-level specifications for the gas coming from the deacidizing plant, i.e. to obtain a gas containing less than 1% by mole of acid gases. Physical solvents allow to absorb large amounts of acid gases when the acid gas contents are high. However, it is more difficult to obtain high-level specifications for the gas treated with physical solvents. It is also well-known to use a mixture of physical solvent and chemical solvent to treat highly acid gases by means of high-level specifications for the gas treated. It is notably known to use a mixture of amine such as DIPA (diisopropanolamine) or MDEA (methyldiethanolamine) with a relatively heavy physical solvent such as Sulfolane used by the Shell company.
Document FR-2,743,083 provides a natural gas dehydration, deacidizing and stripping method using a mixture of physical and chemical solvents.
The present invention aims to improve the method provided by document FR-2,743,083.